The ELWA is also suitable for this type of building, as the piping losses due to the three different locations of the hot water tanks have previously far exceeded the usable energy.

These had been supplied year-round by a central wood chip heating system. This can now be switched off in the summer, with three ELWAs taking over the task using the power of the sun!

No utility approval (EVU) was required for the installation of the devices, which greatly simplified the process for the owner.

For practical pipe routing, the PV systems were placed at two different points on the roof. Since each ELWA has its own MPP tracker, this was easily possible.

Thanks to this technological innovation, the property no longer uses any wood chips in the summer. This is a win for the farmer and good for the environment.

Functionality

During the day, direct current from the PV modules is transported to the ELWA via power cables, which then heats the hot water in the storage tank. On days with low solar radiation, the system automatically switches to using regular household electricity when needed. This ensures that hot water is always available with the ELWA.

An inverter is not required for this form of energy control, as the power is not fed into the grid. This eliminates the need for any connection approvals, and the installation or retrofit is extremely simple.

By using the ELWA, the high energy losses from thermal piping are completely avoided. Solar energy is converted into heat exactly where it is needed.

ELWA Data Evaluation

An integrated data logger enables the visualization of the achieved solar yields, the progression of the hot water temperature, and the amount of energy drawn from the public grid for hot water supply.

ELWA Calculation Tool

The recommended size of the photovoltaic system depends on the number of people in the household and their hot water consumption. It can be assumed that each person uses approximately 50 liters per day, which corresponds to an energy requirement of around 1,000 kWh per year.

The annual yield of a photovoltaic system in Austria is approximately 1,100 kWh/kWp. With a recommended solar hot water coverage rate of 50%, a system output of 2 kWp is suggested for a household of four people.

ELWA Product Details

• 0 – 2,000 W infinitely adjustable

• Target temperature adjustable with rotary knob

• Works even during power outages

• For hot water storage tanks from 100 to 1,000 liters

• Self-consumption 2 W

• Efficiency >99% at rated power

• Hot water backup 750 W